Ebook Mạng thế hệ sau và tiến trình chuyển đổi: Phần 2

C h ittin g 4

M0NG DU&MG TRtlC CUfl VlfT NflM
Vfl TIEN TRlNH CHtlYEN o 6 l SflNG
MflNQ THE HE SflU
Mang vien thong cua Viet Nam se phat trien theo cau true
mang NGN. Tuy nhien, do Viet Nam da co mot mang vifen thong
hien dai va kha hoan chinh, bdi vay phuong an phat trien NGN cua
Viet Nam la “ xay dung NGN trfen co sd mang hien tai” .
Dfe xay dung mang NGN thi xay dung ldp chuyfen tai (bao gom
mang truyen ddn dudng true va mang chuyfen mach) la khau co y
nghla quyet dinh nhat. Do la nhung lap luan va sd cuf dfe thiet kfe va
trien khai trfen tirng giai doan cho phu hop vdi dinh hudng cau true
mang cua Viet Nam.
4.1. P H l/O N G H lfO N G PH AT TR IEN CUA M A NG T R U Y E N
DAN D U O N G T R U C
4.1.1 Cac yeu to phat trien ve dung lupng m ang dudng true
a. So luon g ngudi su du n g tdng
Ngay nay, veu cau vfe dung lupng da dat ra cho mang luon phai
d the siin sang cao do su tang dong thdi cua ca ba nhan to nay. So
lupng ngudi su dung Internet ngay mot tang vdi thdi gian truy cap
tang va dung lupng tai theo yfeu c;\u cung ldn hon. Tuy nhifen sd
ngudi sir dung dien thoai lai tang cham nhung tcing so thdi gian sir
dung difen thoai lai rat cao. Cac nude dang phat trifen chu yeu gop
phan vao sir tang trudng so ngudi sir dung dien thoai, trong khi do
cac nude phat trifen lai gop phan chu yfeu vao tang Internet.


74

Mang the he sau va tien trinh chuyen <56

b. B ang tan cua dich vu tdng
Ben canh so ngudi su dung tang thi cung can ti'nh den su tang
do rong bang tan cua cac ung dung. Doi voi dien thoai chi can do
rong bang 64 kbit/s nhung doi vdi hoi nghi truyen hinh va dien
thoai thdy hinh thi do rong bang tan toi thifeu la 128 kbit/s. Ban d^u
Internet chu yeu dugc sir dung cho truyfen tfep va thu difen tir nhung
ngay nay yfeu cau truy nhap Internet toe do nhanh vai cac luong
thong tin hinh anh va video. Hien nay luu luong Internet tang hon
10 lan trong nam.

c. M uc do su dun g dich vu
Nhan to quan trong thu 3 anh hudng den nhu cau tang ciia
dung luong truyfen dan do la tang thdi gian su dung dich vu ben
canh yeu cau vfe dung luong dich vu se tang nfeu mang dap img
dugc moi yfeu cau ciia khach hang.
Nhu vay, van dfe quan trong nhat dfe phat trien mang la moi
mot quoc gia can co mot su phat trifen mang ciia minh ca ve quy
mo mang va cong nghe. Trong qua trinh phat trifen mang. vifec nang
cap va xay dung mdi mang truyfen dan ma trong do mang chusfen
tai la muc tieu quan trong nham thoa man chuyfen tai luu luong
tang vdi toe do nhanh nhu hien nay. Hon the nua. vifec xav dung
mang dudng true con phai bao dam su linh hoat va an toan cho moi
luu lugng. Qua trinh trifen khai xay dung cac cau true mang cung
phai tinh den 16 trinh chung ciia vifec phat trien mang sao cho viec
khai thac va quan ly mang phai co hieu qua trong suot tien trinh
phat trien ciia mang.
4.1.2 Qua trinh phat trien m ang truyen dan
Cong nghe truyfen d an da co su thay doi qua cac giai doan: tir
tuong tu sang sd. tu phan cap can dong bo (PDH) sang phan cap so

Chuong 4: Mang dudng true cua Viet Nam va.

75

dong bo (S D H ) va gdn d a y la tu S D H sang W D M . Mot cau true
mang moi ra d di dfe h 6 tro va tuong thich hoan toan vdi cong nghe
cu thi cdng nghe chuyen mach mdi phai trung vdi the he cong nghe
truyfen d an trudc.
a. C dn g nghe W DM
Toe do tang trudng ciia dung lupng dudng truyen ciia mot cong
nghe ma khong thoa man nhu cau dung lupng nua, thi cong nghe
mdi tiep theo se xuat hien. Ngay nay cong nghe W D M la cong
nghe dupe xem nhu day hira hen. Trong tuong lai, cong nghe
W D M se phat trifen hon dac biet khi ket hop vdi cac ky thuat xir ly
tin hieu quang nhu ghep kfenh theo thdi gian quang (OTDM),
chuyen mach goi quang cung vdi cac tram lap quang 3R (Repeater)
se m d rong do trong suot ciia mang. Tir do ta cang nhan tha'y do uu
vifet ciia cong nghe W DM .
X a y dung mang NG N sir dung ghep kfenh theo budc song

W D M co nhung uu diem:
+ Tan dung trifet dfe bang tan ciia cap spi quang;
+ Tao ra mot mang truyen d an linh hoat dfe tien tdi mang
truyfen d an quang OTN.
+ Thiet bi W D M ngay cang dupe cai thifen dfe tang dung lupng
truyen dan trfen mot spi quang.
N hd su n 6 lire trong nghifen euru vfe cong nghe W D M gan day
da cho cac ket qua mdi va dung lupng ngay cang cao hon. Mot

trong nhung kfet qua dpt pha co tinh quyfe't dinh ciia cong nghe
W D M dat dupe la giam chi phi thifet bi W D M xuong 10 lan chi
trong 4 nam.
b. C ong nghe O TD M
Ngoai cong nghe W'DM la cong nghe chu dao trong mang
chuyfen tai NGN. trong tien trinh phat trien ciia mang can chu y tdi


Mang the he sau va tien trinh chuyen
76

cong nghe truyen dan ghep kenh quang theo thdi gian (OTDM).
Mac du cong nghe W DM ngay nay rat hieu qua trong viec nang
cao dung lupng, nhung cdng nghe O TD M hien dang dupe phat
trien cung dong mot vai tro chinh de khai thac den cuc dai bang tan
WDM. Su ket hop cua hai cong nghe nay co Ic se m d rong hem nua
gidi han dung lupng.
4.1.3 Cau true mang truyen dan
Qua trinh xay dung mang truyfen dan NGN ap dung cong nghe
WDM cho tuyen diem - difem dfe nang dung lupng. Tuyfen diem diem dung lupng cao chi la budc ddu tifen trong qua trinh khai thac
cong nghe WDM. Cac mang Ring va Mesh W D M su dung cac bo
noi chfeo quang (ODXC) va bo ghep kfenh xen re quang (OADM)
tao nen budc tiep theo trong xu hudng phat trien tdi mang photonic
(hoan toan quang) dung lupng sifeu cao. Cac thiet bi nay can co cac
thanh phan quang trong cau true cua chung de cung cap cac noi ket
giua cac c 6 ng dau vao va dau ra trong qua trinh truyen dan liru
lupng cua mang NGN. Tuy thuoc vao cach tiep can va kien true
dupe su dung ma can co cac bo loc co thfe difeu chinh. cac bo
chuyfen doi budc song, cac bo xen re, cac bo to hop. cac bo chuyen

tiep budc song... Tiep dfen la can co cac bo ngu 6 n. bo tach quang.
bo khufech dai quang va bo ghep/tach kfenh quang MUX/DEMUX)
dfe tao nen tuyfen quang hoan chinh.
Vdi cong nghe SDH, khi xay dung cac mang quang can co su
quan tam ve ki'ch cd cua mang. do ban chat tuong tu cua tin hieu
quang. Rat nhieu cac thanh phan cua mang quang cot tin hieu di
qua theo kieu tin hieu tuong tu (analog). Tuy nhien cac ham truyen
dat cua cac thanh phan nay khong ly tudng va vi vay chung lam
suv giam chat lupng cua tin hieu khi di qua. Trong cac he thong
W DM con xav ra tuong tac da kenh. cac hieu ung phi tuyen lam


77

Chuong 4: Mang dudng true cua Viet Nam va.

suy giam tin hieu khi truyfen qua spi. Vi vay co thfe dinh nghla do
dai thong suot la do dai ma qua do tm hieu quang co the dupe
truyfen trung thuc ma khong co bat cu chuyen doi difen nao.
Xu hudng tien tdi mang toan quang.
Xu hitting
phat trien cong nghe

Ring WDM
ket noi day du

OADM /

._____ ./i'mvfcs

s

.

\oADM A - -----------,'-,-iOADM /

[TTTT \

' r '^ ^ Y J T U T

J^oadm^ ^ oadm/
TTTT

Ring WDM
ket noi tap trung

OADM

I

TTT
\oadm /

;

J

iTTTl \ /
\ OADM

TTTTT

/

17TTT

r OADM
-W/

Truyen dan WDM chuoi co OADM

D-O^ oadm/ ^ oadm/ - ^ ]

lo a d m

TTTT
\ oadm /

TTTTT

TTTTT

Truyen dan WDM diem - diem

1996

1998

2000

H'uih 4.1: Can true mang

2002


Mang the he sau va tien trinh chuyen <36

78

Hinh 4.1 chi ra xu hirdng phat trifen co thfe cua mang photonic
(mang toan quang) tuong ung voi xu hudng phat trien cdng nghe
cua cac khoi co ban. De xay dung nfen mot mang chuyfen tai hoan
toan quang kha thi va co loi ve kinh te thi ngoai thach thuc ban diu
vfe cong nghe dudng truyen quang chat luong cao, cac bo noi cheo,
va cac nut chuyfen mach quang thi con can phai vupt qua thach
thuc vfe cau true mang. Cac thanh phan ca'u true co ban do la cac
topo Ring va Mesh va co thfe t6 hop theo vai cach nhu ket hop
Ring/Mesh, phan cap da Ring.
Ngoai vifec xem xet cong nghe, cac thanh phan ca'u tao dudng
truyfen quang va cau true mang thi cung can phai xem xet den h£
thdng bao hieu va giam sat. Khi xay dung mang thi cung can co su
giam sat xem cai gi se xay ra d trong mang. Trong khi khai thac
chac chan se gap phai cac su kien dupe du ti'nh trudc va cac sir kien
khong xac dinh trudc, doi khi khong mong muon. Do do c£n co he
thong bao hifeu va giam sat cho mang. So vdi mang SDH. thi co rit
nhieu van de can phai dupe de cap trong mang W D M .
Rao can quan trong tiep theo can vupt qua do la phat trifen mot
mo hinh thong tin hieu qua de tri'ch va xu ly tat ca cac trudng thong
tin nhan tir mang. Cac thu nghiem gan day da chi ra rang ap dung
thing cach tiep can mo hinh phan ldp dupe phat trifen cho mang

SDH da nay sinh ra mot sd van de ddi vdi mang W DM .
a. Cau true m ang quang trong tuong lai
Muc tieu ro rang cua cac mang chuyfen tai NGN hien dai do la
cang ho tro nhieu khach hang cang tot va dam bao hieu qua ve chi
phi va an toan trong tuong lai. Mot trong nhung ly do dfe chap nhan
mang truyen dan W D M do la do thong suot cua mang.


79

Zhaong 4: Mang duong true cua Viet Nam va.

SDH

1

ATM

1

ATM

IP

1

1

Giao dien quang md

WDM

Hinh 4.2: Cac ldp kliacli hang tren lap truyen dan quang WDM
Tren co sd cau true phan lop cua mang truyen dan quang theo
nhu cau dich vu va cong nghe nhu tren, co the xay dung cau true
vat ly mang truyen d i n quang nhu sau.
b. M ang truy nhap
- Trien khai spi quang trong mang phi-do (phan tu tdng dai den
bo M UX /tap trung) cang gan tdi khach hang dan cu cang tot de’
phan re bang cap dong co the’ sir dung cong nghe ADSL.
- Tuong tu trong mang lai cap quang va d 6 ng true thi phan spi
quang cang den gan thue bao dan cu cang tot de phuc vu mot so
nho hem thue bao bang cau true mang cap dong true hinh cay.
- Truy nhap cap dong se dan thay the bang truy nhap cap
quang, vi du giai phap lai giua FTTC va cong nghe VDSL cho phep
toe do dudng xuong len tdi 50 Mbit/s.


Mang the he sau va tien tnnh chuy&i ttf

80
(SDH. ATM.
WDM. IP)

10 Mbit/s

50 Mbit/s

Hinh 4.3: Hudng phut trien ciia mang truy nhap va mang chu\en tai

-

Khi nhu can theo du bao den nam 2010 la 100 Mbit/s cho
mot khach hang, thi sc yeu cau dudng truy nhap quang true tiep
den thue bao (FTTH). Xu hudng nay cho thay it nhat 90% mang
truy nhap la cap quang. trong khi chi co 10% la cap dong d thdi
diem c!6 .


Chi/ang 4: Mang dudng true cua Viet Nam va.

81

Ngoai cac co che truy nhap co dinh nay, thi truy nhap vo tuyen
co the se tiep tuc tang trudng va dap umg cac nhu cau khae ve mang.
c. M an g chuyen tdi
Mang chuyen tai se dap ung chuc nang la truyfen tong luu lupng
phat ra tu mang truy nhap. Qua phan tich va nghifen cuu cua cac
nude, co mot sd danh gia da chi ra rang dung lupng dudng truyen co
the dat cd 1 Tbit/s vao nam 2010 va tang lfen dfen 10 Tbit/s vao nam
2015. Hien nay rat nhieu mang dang phat trifen theo kien true SDH
gom cd topo M esh vdi cac DXC ket noi cac Ring.
Dung lupng dudng truyen dudng true hien nay dang dupe nang
cap bang W D M va tdng dung lupng la 32x10 Gbit/s se la kha thi
trong trong tuong lai gan. De nang cap mang mot cach kinh tfe hon
nua thi can tha'y dupe ldp mang truyen dan quang W D M se tuong
tu nhu SDH. N hu hinh 4.3, ta cd mang topo Mesh vdi cac bo noi
cheo quang ket noi cac vong Ring quang. Phfa bfen phai cua so do
chi ra mot hirdng hoi khae do la cdng nghe truyfen dan kieu goi bao
gom cac bo noi cheo goi. Ldp truyfen d in quang do ti'nh trong suot

ma cd the dirpc sir dung de dap ung truyfen dan cac goi nay vdi
dung lupng cao va khoang cach dai.
Tom lai, rat kho dir bao chinh xac xu thfe phat trifen mang truy
nhap va mang chuyen tai vi cd mot sd ly do lam m d rong toe do
thay doi cdng nghe nhu xu hudng tu do hoa va canh tranh trong
cdng nghifep vifen thdng va cdng nghe thdng tin. Vifec quang hoa
mang truyen dan se ngay cang tham nhap vao mang, nhung no xay
ra vao thdi difem nao thi chua biet chac chan dupe.
Cd mot dieu dang luu y la cd den 80% chi phi mang nam d
trong phan truy nhap, do vay hudng nao ma lam tdi thieu chi phi
qua do se rat hap dan. Vi lv do nay, giai phap FTTx cung vdi ky
thuat xDSL cd ve hap dan. cho phep td hop thich hop phan phi-do


Mang the he sau va tien tnnh chuySn d6i

82

bang cap quang va phan phan bo bang cap dong de dap tirng dupe
nhu cau dung lupng. Cac ky thuat cap quang - cap dong true va vo
tuyen cung rat hap dan.
Trong mang truyen dan, su phat trien cua W D M se tao thuan
lpi cho phat trifen den ldp mang truyen dan hoan toan quang. Ldp
nay co the bao gom cac Ring quang noi ket bang cac bo noi cheo
quang. Cau true nay se dap ung dupe nhu cau dung lupng tang len
Terabit du bao trong nhung nam 2020.
4.2. G IA I PH A P N ANG C A P M A N G T R U Y E N DAN DUONG
TRUC Q UO C GIA TIEN T O l M ANG THE HE SAU (NGN)
Tu xu the phat trien mang, viec xay dung cau true mang truyen
dan dudng true cua mang vifen thong Viet Nam dupe xac dinh

nhu sau.
4.2.1 Cau true mang truyen d in dudng true hien tai
- Mang truyen dan dudng true quoc gia hien tai dang khai thac
dupe xay dung trfen co sd cac tuyfen truyfen dan quang cong nghe
SDH va cac tuyfen vi ba.
- Cau true dang Ring va Mesh la chu yfeu. Tuy n'.uen trong
mang lifen tinh, cac tuyfen thang diem - difem van con dang kfe.
- Tuyfen dudng true Bac - Nam la tuyen truyfen dan 2.5 Gbit/s
la sir kfet hop cua hai tuyfen cap spi don mot theo dudng 1A va
dudng difen lire 500 kV.
4.2.2 D inh hudng xay dung m ang truyen dan dudng true
quoc gia
Dinh hudng vifec nang ca’p mang truyfen dan dudng true quoc
gia nen dupe tifen hanh lam 2 giai doan:


83

Chuong 4: Mang dudng true cua Viet Nam va.

- Giai doan /: Tiep tuc str dung cong nghe SDH ket hop vdi
cong nghe WDM. Thuc hien cai tao va nang cap cong nghe SDH
dfe san sang dap ung vifec chuyen tai cac luu luong IP, ATM
- G iai doan 2: Tifen hanh xay dung mang chuyen tai dua trfen
OTN. Cuoi cung la thuc hien truyen true tiep luu luong IP/MPLS
qua spi quang.
XSy dung mang truyen dan dupe bam sat theo cau true mang
PSTN cd to chuc thanh cac vung luu lupng vdi muc tifeu tang nang
lire mang Toll hien co giai doan 2001-2005 nhu sau:
+ Trang bi mdi tong dai Toll HDG, Toll DGN2

+ Thay the cac tdng dai TDM kieu cu bang he thdng tong dai
cong nghe mdi dam bao day du cac ti'nh nang can thifet.
+ M d rong nut tong dai Toll Ha Noi, TP. Ho Chi' Minh.
Hd Not

N in g

TP H6 Chi Minh

Hinh 4.4: Cau true chuyen much PSTN giai doan 2000-2005
Trfen co sd do thuc hien xay dung mang truyen dan theo:


84

Mang the he sau va tien trinh chuySn d6

a. Phan vung luu luong
Cau true mang the he sau dupe xay dung dua tren nhung vung
luu lupng. Phan vung luu luong va dua vao phan b6 thue bao theo
vung dia ly, khong to chuc theo dia ban hanh chinh.
b. To chuc lap ting dung va dich vu
Ldp ung dung va dich vu dupe to churc thanh mot cap cho toan
mang nham dam bao cung cap dich vu den tan nha thue bao mot
cach thong nhat va dong bo. So lupng nut ung dung va djch vu phu
thuoc vao luu lupng dich vu, so lupng va loai hinh dich vu, va dupe
to chuc thanh cap (Plane A&B), phan tan theo dich vu nham dam
bao tm h an toan he thong.
Nut ung dung va dich vu dupe ket noi d muc Gigabit Ethernet
1+1 vdi nut dieu khien dat tai cac Trung tam mang NGN d Ha Noi

va TP. H 6 Chi Minh.
c. To chuc lap dieu khien
Ldp difeu khien co chuc nang dieu khien ldp chuyen tai va ldp
truy nhap cung cap cac dich vu cua mang NGN, g 6 m nhieu modun nhu mo-dun dieu khien ket noi ATM , dieu khien dinh tuyen
ket noi IP, dieu khien ket noi cuoc goi thoai, bao hieu sd 7... Ldp
dieu khien dupe t 6 churc thanh 2 cap cho toan mang thay vi co 4
cap nhu trudc day va dupe phan theo cac vung luu lupng.
Sd lupng nut dieu khien phu thuoc vao luu luong cua tirng vung
va dupe to churc thanh cap (mat phang A&B) nham bao dam tinh an
toan cho he thdng. M 6 i nut dieu khien dupe ke't noi vdi mot cap nut
chuyen mach ATM +IP dudng true.
d. To chuc l&p chuyen tdi
Ldp chuyen tai phai co kha nang chuyen tai ca hai loai luu
lupng ATM va IP dupe t 6 chuc thanh hai cap: dudng true quoc gia
va cap vung thay vi 4 cap nhu nam 2000.


Chuong 4: Mang dudng true cua Viet Nam va.

85

+ C ap dudng true quoc gia: gom toan bo cac nut chuyfen mach
dudng true (Core ATM+IP) va cac tuyen truyen d in duong true
dupe to churc thanh hai mat phing A&B, ket noi cheo giua cac nut
dudng true tdi thieu la 2,5 Gbit/s.
+ C ap vung: gom toan bo cac nut chuyfen mach (ATM+IP), cac
bo tap trung ATM noi vung bao dam vifec chuyfen mach cuoc goi
noi vung va tir vung nay sang vung khae. Cac nut chuyfen mach
(ATM+IP) noi vung dupe kfet noi d muc tdi thieu 155 Mbit/s lfen ca
hai mat chuyen mach cap true qudc gia qua cac tuyen truyen d in

noi vung. Cac bo tap trung ATM dupe ket noi d muc tdi thifeu lfen
cac nut chuyen mach (ATM+IP) noi vung va d muc tdi thifeu nxEl
vdi cac bo truy nhap.
Cac nut chuyen mach ATM +IP noi vung dupe dat tai vi tri cac
tong dai Host hien nay va dupe kfet noi true tiep vdi nhau thong qua
cac cong quang cua nut ATM+IP, sir dung cac spi quang hien co
trong tuyen mach vong spi quang cua mang noi vung. Cac nut
chuyfen mach A TM +IP noi vung phai tich hop ti'nh nang Broadband
RAS n h im thuc hien churc nang diem truy nhap IP POP bang rong
cho cac thufe bao xDSL.
Sd lupng va quv mo cac nut chuyen mach ATM +IP ciia mot
viing trong giai doan dau phu thuoc vao nhu cau dich vu tai vung do.
Cac bo tap trung ATM co nhiem vu tap trung cac luong E l le
thanh luong ATM 155 Mbit/s. Cac bo tap trung ATM dupe dat tai
cac nut truyen d in noi tinh. Sd lupng va quy mo tap trung ATM
phu thuoc vao sd nut truy nhap va sd thufe bao ciia nut truy nhap.
e. To chuc lop truy nhap
Ldp truy nhap gom toan bo cac nut truy nhap dupe t 6 chuc
khong phu thuoc theo dia gidi hanh chmh. Cac nut truy nhap cua


Mang the he sau va tien tnnh chuy6n <36\

86

cac vung luu luong chi duac ket noi den nut chuyen m ach dudng
true (qua cac nut chuyfen mach noi viing) cua vung do ma khong
dupe ket noi dfen nut dudng true cua vung khae.
Cac kfenh kfet noi nut truy nhap vdi cac nut chuyfen mach noi vung
co toe do phu thuoc vao sd luong thufe bao tai nut. it nhat la nxEl.

Cac thiet bi truy nhap the he sau phai co kha nang cung tap
cong dich vu POTS. VoIP. IP. ATM. FR. X.25. IP-VPN. xDSL...
4.2.3 Xay dung mang truyen dan dudng true quoc gia tien tdi
NGN
a. C au true m ang
Vifec xay dung mang truyen dan dudng true quoc gia phai dua
tren nguyen tac chung va cau true ldp chuyfen tai cua qua trinh phat
trien mang NGN. nham muc tieu dat duac mang truvfen dan do
chuyfen tai luu luong ldn thong suot doc quoc gia tien tdi NGN. Vi
vav cau true cua mang truyen d in co the duac xay dung dua tren
co sd mang hinh 4.5.
Trong cau true mang truyfen d in co su ke thua cua cau true
mang hien tai va cac cong nghe dang sir dung. Do do van tan dung
cau hinh Ring cap trong viec xav dung mang. Cac thiet hi truyen
dan tren tuyen truyen dan dudng true la cac thiet hi du manh ve
nang lire de bao dam thong suot luu luong cao va phu hctp vdi cau
hinh hao an luong.
b. M o i tru d n g truyen dan
De xay dung mang truyen dan dudng true quoc gia.

hai hinh

thuc truyfen dan chinh duac ap dung cho mang la: truvfen dan cap
quang va truyen dan vi ha.


Chuong 4: Mang dudng true cua Viet Nam va.

87

- Vi ba: Cac tuyen vi ba chi la tan dung cac tuyen hien co (toe
dp 140 Mbit/s hien nay). Khong xay dung cac tuyen vi ba moi
trong thdi gian nang cap len NGN.
- C ap quang: Cac tuyen cap quang tiep tuc dupe xay dung mdi
bdi vi chi co cac tuyen cap spi quang mdi du nang luc va hoan toan
phu hop vdi yeu cau cua mang chuyen tai trong tuong lai. Cac dac
die’m cua cac tuven cap quang:
- Bang tan rong len tdi 200 THz chinh day la moi trudng
truyen d in ly tudng cho su bung no dich vu mdi.


88

Mang the he sau va tien tnnh chuyen d6i

- Bang tin rong len tdi 200 THz chinh day la moi trudng
truyfen d in ly tirdng cho su bung no dich vu mdi.
- Suy hao nho tao ra cac cu ly truyen d in xa. it phai d iu tu cac
tram lap hay khufech dai va rat phu hop vdi khoang cach giua cac
dia ban tinh thanh d nude ta vdi toe dp lu 6 ng 2,5 den 10 Gbit/s.
- C h it lupng dich vu cao la yeu c iu ldn cua m ang chuyfen tai se
dupe cac tuyen truyfen d i n cap quang dap ung.
- Truyfen d in cap quang hien la cong nghe tifen tien nhit va
cung v in dang tifem tang phat trien, thfe hien tinh linh hoat md rong
cho cong nghe hien dai.
- Da dupe khai thac pho bifen d nude ta. Nhieu tuyfen da dupe
khai thac co hieu qua, do tin cay cao, dac biet cho cac tuyfen dudng
true va lien tinh.
- D iu tu hop ly va co hieu qua trong mang dudng true.
c. C ong nghe truyen dan

Vfe cong nghe truyfen d in , trfen co sd xu hudng phat trien chung
ciia mang NGN va c ic dac thu cua c ic cong nghfe truyfen din,
mang dudng true quoc gia c in phai duac xav dung trfen nen tang
cong nghe SDH va cong nghfe quang W DM.
c l . Cdng nglie SDH
Uu difem:
- Cong nghfe truyen d in quang SDH da dupe su dung thanh
cong trong cac c iu true don kfenh.
- Kha nang giam sat. quan ly bang tan kha tot
- Phu hop vdi dich vu thoai va thue kfenh rieng.
- Ca chfe du phdng. phuc hoi. an toan mang


Chuong 4: Mang dudng true cua Viet Nam va.

89

Nhugc diem:
- Kho khan trong viec m d rong mang va quan ly khi bung 116
dich vu mdi.
- M d rong mang dong nghla vdi viec lap dat mdi cap va he
thdng
- Djnh tuyen mang thong qua khe thdi gian, nen khong linh
hoat, phurc tap va bj han che.
c2. Cong nghe W D M
Ifu diem:
- Bang tan sai quang rat ldn.
- Khong han che trong viec m d rong mang va quan ly khi bung
no djch vu mdi (dac biet khi ket hop vdi SDH): M d rong mang
thong qua viec them kenh quang (W DM, OTDM), khong b it buoc

phai lap dat mdi cap va he thdng.
- Djnh tuyen mang thong qua dieu khien cac kenh quang.
Nhifoc diem:
- Giam sat, quan ly kenh quang con bat cap.
- Kha nang phuc hoi nhanh chong cua kenh quang chua
hoan thifen.
4.2.4 Tien trinh chuyen doi mang truyen dan NGN cua Viet Nam
Viec xay dung cau true mang truyen dan quoc gia dugc tien
hanh theo 2 giai doan n hu sau:
I) G iai doan 1 (2001-2005)
a. C an true
- Hoan thanh nang cap mang cap quang dudng true Bdc-Nam
len 20 GHz bang viec su dung ky thuat WDM difem noi difem


Mang the he sau va tien trinh

90

chuySn d6i

(diem-diem W D M ) vdi so kenh quang la 8 budc song, tdc do STM16 cho moi mot kenh. Mang dudng true quoc gia gom 4 vong King
(W DM) tdc do 20 Gbit/s do la vong 6 , 7, 8 , 9.
- Hoan thien tuyen cap quang doc dudng Ho Chi Minh theo
tien do hoan thanh tuyen dudng cua Bo Giao thong Van tai.
- Cau true mang dudng true se gom 6 vong Ring SDH dupe ket
noi vdi nhau v in bang cac thiet bi noi cheo sd DXC. bao dam an
toan cho cau hinh bao an luong SDH trong mang chuyen tai TDM.
Dang hoan thien Ring thur 6 tu TP. HCM qua My Tho. Can Tho va
khep kin tai TP HCM.

- Cac dia ban co luu lupng ldn di qua v in giu cac thiet bi xen
re ADM
- Tuyen tren dudng day 500 kV chuyen sang cau true theo
tuyen thin g, va du phong cho mang.
- Chuan bi tien hanh tuyen cap quang bien Bic-Nam.
Cau true va ket noi mang true quoc gia vdi mang truy nhap tien
tdi NGN.
Muc tieu nham hoan thien kha nang sir dung SDH va co the
thuc hien chuyfen tai IP. ATM va m d rong luu lupng truyfen d in va
kha nang chuyen tai cua SDH.
N han x et: Day co the coi la giai doan trung gian dfe chuin bi
tien tdi mang OTN theo NGN.
b. Phan tich can trite mang
- Trfen mang dudng true, vi tri cac nut truyfen d in dudng true
can bo tri tai cac nut chuyfen mach quoc gia va quoc tfe.
- Trfen mang noi hat. cac nut truyen dan noi hat ducac nut chuyen mach noi hat. cac dia difem tap trung xen re. chuven
doi luong va cac difem co hirdng phat trien manh.


Chuong 4: Mang dudng true cua Viet Nam va.

91

- Cac diem truy nhap trong mang truy nhap dupe bo tri tai cac
nut truy nhap va cac diem co su tap trung, thay d 6 i luu lupng.
- Loai difem ket noi bao gom: true-true, truc-noi hat. noi hatnoi hat va noi hat-truy nhap.
- Thu tu viec nang cap hoan thien cong nghe SDH can uu tien
theo:
+ Ket noi giua cac difem xen re va kfet noi trfen cac Ring SDH

trfen tuyfen true.
+ Kfet noi giua cac difem xen re trfen Ring SDH noi hat va giua
noi hat vdi tuyfen true.
+ Cac Ring dupe hoan thien theo nguvfen tac Ring 4 spi.
2) G iai doan 2 (2005-2015)
Trong giai doan nav, can phai xay dung dupe mang truyfen d in
dudng true vdi cac life thdng sir dung ky thuat Loop W D M kfet hop
vdi cong nghfe Ring SDH.
a. Can true
Day dupe coi la giai doan cuoi cung dfe co mang OTN dap ung
NGN.
- Mang dupe tifep tuc dupe nang cap trfen co sd tuyfen true Bac Nam va tuyfen doc dudng day 500 kV, va tuyfen cap quang doc
dudng Ho Cln' Minh theo hudng hoan toan quang.
- He thdng sir dung ky thuat Loop W DM bao trum lfen mang
chuven tai SDH de tao ra OTN. So kfenh quang la dii va can b in g 8
budc song, tdc do S T M -16 cho m 6 i kfenh.
- Cau true gom 6 vong Ring dupe kfet noi vdi nhau bang cac
thiet bi O D X C de thuc hien dinh tuyfen luong quang. tuy nhien
budc dau khong nhat thifet phai trang bi hoan toan ODXC.


92

Mang the he sau va tien tnnh chuySn d6

- Cac dia ban co liru lupng ldn di qua duoc trang bi thong nhit
cac thiet bi xen re O A D M
- Tuyen tren duong day 500 kV chuyfen sang cau true du phong
theo tuyfen th in g kfet noi qua ODXC.
Cau true va kfet noi m ang true quoc gia OTN vdi mang truy

nhap trong NGN
Muc tifeu la tao ra mang truyen d in duong true OTN trong
mang NGN.
Thuyfet minh nguyfen tic kfet noi cau true mang
Day duoc coi la giai doan cuoi cung dfe co mang OTN dap umg
NGN
- Cac thifet bi ODXC dupe dung trong c iu true mang dfe dinh
tuyfen lu 6 ng va tao su thong suot trong vai tro chuyfen tai tai diem
kfet cuoi mach vong WDM.
- Cac trung kfe noi hat tai 3 thanh pho Ion: Ha Noi. TP. Ho Chf
Minh va Da N ing co the duoc ket noi voi mang true thong qua
ODXC khi Ring noi hat duoc nang ca'p bang W D M voi cac luong
quang can b ing voi mang true.
- Mang Ring SDH tai mang lap noi hat sir dung 4 sai vcri dung
luong tuong duong toe dp < 2,5 Gbit/s. Khi Ring noi hat dupe nang
cap lfen W DM d giai doan nay, vifec xen re kfenh thong qua OADM
de thuc hien dinh tuyen va bao an lu 6 ng quang.
- Khi cac mang true, noi hat va vifec kfet noi d trong va giura
chung thong qua luong tin hieu quang trong giai doan nay chinh la
su ra ddi OTN cho NGN.
3) To chuc m ang dudn g true co tinh den thong tin ve tinh noi dia
M ang thong tin vfe tinh noi dia Viet Nam trong tuong lai se dap
ung nhu cau thong tin cho mang vifen thong. Nhu v j \ sfe co tie


Chuong 4: Mang di/dng true cua Viet Nam va.

93

dong toi cau hinh mang duong true. Trong trudng hop nay, mang

dupe mo ta nhu sau:
Cac tram mat dat cua mang thong tin ve tinh duong true se
dupe dat tai cac thanh pho va trung tam cua cac tinh Lon n im tren
duong true thong tin Bic - Nam. M 6 i tram dfeu co cac cong dau noi
ra tong dai PSTN tai tinh do. Dung lupng cua cac tram dupe phan
bo nhu to hop cac kenh 32 kbit/s theo ma hoa ADPCM.
Cau hinh mang thong tin ve tinh nhu sau:
- M ang thong tin ve tinh duong true dong vai tro du phong va
phan tai luru lupng cho mang dudng true hien tai, do vay mang
dupe to chuc theo cau true mang ludi dam bao thuc hien cac kenh
dau noi true tiep gitra cac tram vdi nhau. Cac tram se dung chung
theo phuong thuc da truy nhap TD M A co dung lupng b in g tong
dung lupng mang.
- M ang thong tin ve tinh cung se h 6 trp truyfen d in lifen tinh.
N hu vay, trong truong hop tinh ca den thong tin vfe tinh thi
mang truyfen d in duong true quoc gia se co cau hinh m it luoi. Dieu
nay phu hop voi xu the chung cua tien trinh phat trifen mang da
dupe gidi thifeu d p h in trfen.
4.2.5 Lo trinh nang cap mang truyen dan duong true tien tdi NGN
4.2.5.1 N guyen tdc co ban
Hien nay c iu true mang chuyen tai VNPT dua trfen cong nghfe
SDH. Khi nang cap mang lfen he thdng dung lupng cao hon thi vifec
duy tri tinh hien tai va c iu true cua mang la mot trong nhung yfeu
c iu rit quan trong. Do do, c iu true mang d lop vat ly cap spi quang
thudng it thay doi va dupe coi nhu da x ic dinh nhu d trfen.
Trong q u i trinh chuyfen ddi, c in phai tuan theo cac yfeu c iu sau:


Mang the he sau va tien trinh chuySn d6t

94

- Khong lam anh huong tdi viec cung cap cac dich vu vien thong
- Viec chuyfen doi phai thuc hien theo su uu tien ve nhu cau thi
trudng va thuc hien thong qua tung budc.
- Chu y vifec phan tai luu luong dich vu, dac biet la Internet.
- Bao dam cung cap dich vu truy nh&p bang rong tai cac thanh
pho ldn nhu Ha Noi, TP. Ho Chi Minh, Da Nang, va tiep theo la
mot sd thanh pho khae.
- Bao dam nguyfen tic hoan von.
Ve nguyfen tdc chung can thuc hien nhu sau:
- Phai tuan thu vifec chuyen doi tirng budc.
- l / u tifen mang dudng true va lifen tinh trudc nham trudc mat
dap ung cac nhu cau vfe thoai va truyfen sd lifeu lifen tinh.
- Phat huy hieu qua sir dung nang luc cac tuyen truyen dan
dudng true, dac biet la cac tuyfen cap quang.
- Thuc hien co trong difem ddi vdi cac mang noi tinh. uu tien
cac thanh pho va tinh thanh co nhu cdu nhifeu ve truyen sd lieu,
Internet va cac dich vu bang rong.
- Tiep tuc uu tien xay dung mdi cac tuyfen truyen dan quang,
nang cap cac tuyfen hien co de du sire tiep can vdi mang NGN.
Ngimg trang bi mdi cac he thdng truyfen d in vi ba.
- Can xem xet cac he thdng thifet bi truyfen dan mdi theo hudng
dap ung yfeu cau cho mang trong tuong lai, cho kha nang m d rong
nang cap thuan loi.
Trong phan nav. vifec to chuc xay dung mang dfe mang lai hieu
qua duoc xac dinh bao gom: sir dung mang Ring W D M trfen nen
cap soi quang nhu the nao va ket hop cong nghe Ring ao SDH va
cac cong nghe IP trong tuong lai khi trien khai trfen nfen W D M nhu

Chuong 4: Mang dudng true cua Viet Nam va.

95

the nao cho hieu qua. Vi vay, co the dua ra mot so nguyen tac
chuyen doi cong nghe chu yeu sau:
- Ap dung phuong an he thong dudng true da ldp, trong do:
+ Ldp cao nhat (mang dudng true): la ldp cao n h it thu nhan
luu luong truyfen giua Ha Noi, Da N ing, Quy Nhan, Nha
Trang va Ho Chf Minh.
+ Ldp giua (mang noi vung): La ldp giua m d rong mang
SDH tdi 64 tinh thanh trong ca nude.
+ Ldp thap nhat: La ldp thu nhan luu luong gitra cac P&T va
truyen luu luong nay tdi ldp giua.
- M d rong co cau dau vong: Co cau d iu vong vdi cong nghfe
SDH trfen soi quang la mot cau hinh co ban va quang trong trong
mang sd.
- Ap dung cong nghfe W D M co dung luong truyen d in ldn.
Trong thdi gian g in day. W D M dang duoc gidi thifeu chu yfeu d
My. He thdng nay nang cao dung luong truyen d i n trfen mot soi
quang, hien tai co thfe truyen duoc tdi 40 Gbit/s (16xSTM-16) va
trong tuong lai khong xa la truyfen duoc dung luong tdi 400 Gbit/s.
U u difem cua W D M la kha nang tang dung luong trfen soi hien co
m i khong c in phai lap dat thfem soi mdi. H iu hfet luu luong duoc
truyfen trfen dudng true nfen W D M la giai phap thich hop n h it cho
mang dudng true. Vdi nhung uu difem cua cong nghfe W D M vifec
lua chon c iu true mang su dung IP/SDH/WDM nhu trfen la mot
phuong an thich hop cho mang dudng true Viet Nam.
4.2.5.2 Lo trinh nang cap m ang

a) Giai doan I :
Day la giai doan dua trfen c iu true va hien trang mang hien tai
la chu yfeu dfe thuc hien vifec nang c ip bo sung ca ve chuc nang


96

Mang the he sau va tien tnnh chuyen
thiet bi va kha nang truyen d in dap umg nhu cau tang luu lugng
hien tai va trong cac nam toi.
Viet Nam dang trong qua trinh phat trifen mang NGN cua
minh. Giai doan 1 duoc chia thanh 2 budc. Budc 1 vua kfet thuc vao
dau nam 2004 voi vifec trifen khai rong rai mang truy nhap su dung
cong nghfe ADSL va mang loi. Chung ta dang b it kip vdi tdc do
phat trifen chung cua cac nude trfen thfe gidi va trong khu vuc. Voi
cach tiep can phat trien ADSL, sau do xay dung m ang chuyen tai
va cung cap cac dich vu trfen nen mang NGN l i rit hop ly.
Can hinh:
- Giu nguyfen ciu hinh mang truyen d in dudng true nhu hien
co ddi vdi cac tuyfen truyfen dan dang khai thic.
- Xay dimg tuyfen cap doc theo dudng Ho Chf Minh va hoan
thanh tuyfen nay sdm de kip dua vao khai th ic, va hinh thanh co so
mang true mdi.
- Tao vong Ring thu 5 trfen co sd 4 vong Ring hien co. Dong
thdi tao vong Ring thu 6 tu TP. H 6 Chi Minh qua My Tho. Cin
Tho. Co the coi vong Ring thu 6 nay thuoc mot trong cac Ring khu
vuc phia Nam.
- Cd the tiep tuc khai thac cac vong Ring hien tai.
Thiet bi:

- C huin bi cac phuong an nang cap thiet bi: Nang cap hoan
thien cac chuc nang he thdng thiet bi vdi cong nghe SDH. Xem xet
cac tinh nang ky thuat cua thiet bi, dac biet l i cac tinh nang co ban
de co nhan xet cu the trong cac ung dung khai thac tiep theo.
- Dua them cac mo-dun xu ly luu lugng kife’u goi (IP va ATM).
Trong giai doan nay. trudc het can co khao sat de kfet luan vfe chuc
nang chuyen tai IP va ATM cua he thdng thiet bi ghep kenh TDM.


Chuong 4: Mang duong true cua Viet Nam va.

97

roi tien hanh nang ca'p. Nhin chung, giai phap tot nhat la ket noi
them cac thiet bi hoac thay the hoan toan thiet bi nfeu can thiet.
Viec can thifep true tiep vao thiet bi khong bao dam tinh phu hop ca
vfe ky thuat va tinh hieu qua cua no.
- Cac mo-dun xu ly nay chi them vao tai nhung noi co nhu cau
xen re luu lupng goi.
- Ket noi cac vong Ring bang thiet bi DXC de bao dam hoan
thien cac chuc nang bao an cua cong nghe truyfen dan SDH dupe
xay dung trfen co so ca'u hinh Ring.
Budc 2 tien hanh cac cong vifec nham chuan bi nang lire cho
mang truyen dan du dfe c h u in bi cho giai doan nang cap va xay
dung mang thfe he sau NGN. Vi vay co the thuc hien nhu sau:
Can hinh:
- Hoan thanh xay dung ca'u hinh mang truyfen d i n duong true
theo tuyen 1A, duong Ho Chi Minh, va tuyen truyen d in trfen
duong day 500 kV vao nam 2004 theo ca'u hinh g 6 m 6 vong Ring

khep kin. Cac Ring nay v in kfet noi voi nhau b in g thifet bi DXC va
bao an bang cong nghfe SDH.
- Nang ca'p b in g cong nghfe W D M theo tirng tuyen rifeng re
theo nhu ciu. Tao cau hinh W D M diem noi diem trfen tirng tuyfen
truyfen d in rifeng re. Dfe thuc hien nang cap trong giai doan nay,
trudc hfet can kiem tra lai ta't c i cac spi trfen tuyfen cap de khin g
dinh gia tri suy hao va tan sic cho phep. Lo trinh nhu sau:
+ Xac dinh c ic gia tri suy hao va tin sic spi d in quang
hien co dfe thifet kfe theo phan bo suy hao va tan sic.
+ De nguyfen tinh trang hoat dong cua tuyfen hien tai. Thuc
hien nang cap trfen doi dir phong